Phoenix Still Has Chromium-6 in Its Water, and Who Knows If It's Dangerous

"Is Phoenix tap water safe to drink?" the City of Phoenix's Water Services Department asks itself in a Q&A document.

"Phoenix tap water meets or surpasses all federal and state requirements for health and safety," it answers in the document revised last week. "More than five million tests and measurements are performed each year in the water treatment and distribution systems. Phoenix's state of the art equipment and laboratories are used to test for more than 100 substances. Be assured that if water quality is ever an issue in Phoenix, customers will be notified."

Notice that the answer isn't, "Yes."

Last night, PBS Newshour aired its report on a substance called Chromium-6 (or hexavalent chromium) in the drinking water in the United States -- the substance that made Erin Brockovich's work into a movie.

The news report revisited Hinkley, California, where Brockovich played a role in getting a settlement from a utility company, Pacific Gas & Electric,which caused a contamination of the drinking water by dumping a chemical in ponds.

The town still seems pretty screwed up, but that's just one piece of the report on Chromium-6, which was found to cause cancer when it was in high levels of the drinking water of rats and mice.

Phoenix was one of 35 cities where the tap water was studied by the Environmental Working Group in 2010, and Chromium-6 was found in 31 of those cities, including Phoenix.

The problem is, nobody seems to agree on what is the safe level of this substance in tap water.

The EPA set its standard 20 years ago at 100 parts per billion -- "based on the best available science at the time," the agency says -- while the California EPA set a "public health goal" at .02 (point-zero-two) parts per billion.

Since then, the EPA has all but admitted that the 100 parts per billion number isn't acceptable.

"The science behind chromium-6 is evolving," the agency said in a 2011 press release. "The agency regularly re-evaluates drinking water standards and, based on new science on chromium-6, has already begun a rigorous and comprehensive review of its health effects."

So, at the moment, there's really no answer from the EPA on what's acceptable, and there appears to be a lot of steps involved before the EPA adjusts its number -- "if a new standard needs to be set," according to the EPA website.

Phoenix was found to have 0.19 parts per billion, which is way, way below the EPA's current standard. Also, Scottsdale was found to have 0.05 parts per billion, putting them both above California's recommendation, but way below the federal standard. (Phoenix was about in the middle of the 31 cities.)

According to the city's document referenced above, the city itself will start monitoring the water supply for Chromium-6 starting this year, as part of new EPA regulations.

Basically, who knows if there's a danger in Phoenix's tap water, as far as Chromium-6 is concerned. However, it sure sounds like the city's playing by the (current) rules for this chemical, although it's really not that reassuring.